Accordingly, the method of image pick-up by a scanner in the traditional manner has already been well known to the general business widely. The typically picked up image is stored in the memory by the manner of a digital formation of image element data array. The common types of scanner include: the roller scanner, the flatbed scanner, the two-dimensional scanner, and the palm scanner, etc. For any kind of above-mentioned scanners, it always proceeds a picking-up motion of scanned data on the image.
During the common procedure of scanning by a scanner on a specific image to be scanned, every single point constituting the image, that may be constituted by extremely many single points, may be scanned by the scanner, but usually the response of the darker part of an image is smaller, so it may easily be interfered with by noises. The originally unnecessary noises may be generated during the scanning procedure. The scanning quality of the entire image may therefore be influenced.
Since the noise is unpredictable and its occurrence is out of expectation, so it usually depends on the software design of a scanner to improve the performance and overcome the problems created by the poor quality of the manuscript. In general, it is impossible to require the manuscript image to maintain an extremely high quality. Further, the design quality of the scanner itself is also a main factor of influencing the scanning quality. Therefore, it often occurs the situations that the obtained data has too large difference from the reasonable data or the data after being scanned has great deviation from the original image. Thus, how to solve this kind of problem has become the most important topics nowadays.